In general, a boot is secured on a ski by a front binding and a rear binding. To allow the adaptation of these bindings to the length of the sole of the boot, the rear binding is mounted so as to slide longitudinally along a slide track assembled to the ski. A bolt, or any other locking means, allows a well-defined longitudinal position to be imparted to the body of the binding. From this position during skiing, the body of the binding can be pushed back against the elastic return force of a spring. This backward motion occurs, in particular, when the ski is flexed.
The slide track is assembled on the ski using screws. Most often, during mounting, these screws are tightened by electric or pneumatic screw drivers equipped with a jaw-coupling device which disengages the blade of the screw driver when the screw exhibits resistance to rotation greater than a pre-adjusted moment of forces. Generally, this resistance is reached when the threaded part of the screw reaches a sufficient level of attachment inside the ski.
However, it may occur that the screw does not exhibit sufficient resistance to case the disengagement of the screw driver, in particular given the inertia of the moving part. In this case, the screw turns loosely in its hole while tearing away ski material, which adheres to this threaded portion. A special operation then becomes necessary to repair the housing and allow a new screw to be screwed in place.
This difficulty becomes particularly troublesome when the screw holds the slide track in place by means of a plastic covering which encloses the slide track. In this covering, a hole is provided to house the screw head.
For this device, the friction between the screw head and the hole in the plastic covering is not enough to sufficiently slow the screw at the end of the screwing operation and to cause the screw driver to disengage. Accordingly, at the end of the screwing operation, the hole in the covering piece does not exhibit sufficient resistance to the screw head to stop its rotation. The screw head continues to pivot, but, since it cannot continue its descending motion, the ski material is torn away and rises along its threading.
There are other mounting device which use a clamp, or auxiliary piece. The screw head then rests on a harder surface, which stops its rotation more effectively. However, this device has the disadvantage of requiring an additional part, i.e., the clamp, thus raising the cost of the binding.